1. Field of the Invention
This invention relates to an after-recording apparatus or a dubbing-in apparatus which is designed to post-record, for example, an audio signal in connection with main data including audio data and video data. In addition, this invention relates to a computer program, a recording medium, a transmission method, and a reproducing apparatus.
2. Description of the Related Art
Japanese patent application publication number 11-144378/1999 discloses a method of after-recording (post-recording) in which original data including a video bit stream are read out from a digital recording medium. The read-out original data are decoded. Audio data are encoded into a new audio bit stream in synchronism with the decoding of the original data. The new audio bit stream is written into an area of the digital recording medium which approximately corresponds in time position to the original-data recording area.
Japanese patent application publication number 11-259992/1999 discloses an optical disc on which the post-recording (the after-recording) of new data can be implemented. The optical disc in Japanese application 11-259992 stores a stream of packs including normal packs and reserved packs. The normal packs are loaded with original moving-picture data. Initially, the reserved packs are unoccupied. New data such as audio data can be written into the reserved packs. The original moving-picture data and the new data can be simultaneously reproduced from the optical disc.
Japanese patent application publication number P2000-197005A discloses an information recording medium having an area “A” and an area “B”. The area “A” stores a stream of packs including video packs and audio packs. The area “B” stores a table having first, second, and third information pieces. By referring to the first information piece in the table, a decision is made as to whether or not audio data in the audio packs in the area “A” correspond to silence. In the case where the audio data in the audio packs correspond to silence, post-recording (after-recording) can be implemented as follows. By referring to the second and third information pieces in the table, a new audio signal is encoded into new audio data, and the new audio data are formatted into new audio packs. The new audio packs are written over the old audio packs in the area “A”.
Recently, multiplexed data containing video data and audio data have sometimes been handled as a form of a transport stream or a program stream. Generally, it is difficult to replace only audio data in such multiplexed data with new data.
Prior-art post-recording (prior-art after-recording) writes new audio data so that an original multiplexed main stream is converted into a new one. Generally, it is difficult to convert the new multiplexed main stream back into the original one.
In the prior art, it is difficult to post-record a plurality of new audio signals, and to select one from the new audio signals during playback.